Method of forming a staple for use in surgical procedures

ABSTRACT

A staple is provided having a backspan and a first and second legs extending distally from the backspan. Each of the first and second legs includes a bend dividing each leg into a traversing leg portion and a substantially linear clenching leg portion. A staple plate is positionable over the first and second legs between the backspan and the first and second clenching leg portions. An anvil assembly has first and second movable members which move toward to one another to engage outer surfaces of the first and second clenching leg portions. There is further disclosed a method of forming the staple through tissue.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a divisional application of and claims thebenefit of and priority to U.S. patent application Ser. No. 13/450,753filed on Apr. 19, 2012 by Heinrich et al., which is a divisionalapplication of and claims the benefit of and priority to U.S. patentapplication Ser. No. 12/486,819 filed on Jun. 18, 2009 by Heinrich etal., which claims the benefit of and priority to U.S. ProvisionalApplication No. 61/082,852 filed on Jul. 23, 2008 by Heinrich et al.,the entire contents of each of these applications are incorporatedherein by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to a surgical staple for use in surgicalprocedures. More particularly, the present disclosure relates to asurgical staple and a staple assembly configured to accommodate variousthicknesses of tissue by assuming a box configuration upon formationthrough tissue. The present disclosure also relates to a method ofstapling tissues of various thicknesses with a single, uniform sizestaple.

2. Background of Related Art

During various surgical procedures it is often necessary to secure oneor more tissue sections together or to secure auxiliary structures suchas, for example, mesh, buttress material, etc. to tissue. This istypically accomplished by driving a conventional staple, having abackspan and a pair of legs extending from the backspan, through thetissue and/or through the auxiliary structure. Once the conventionalstaple has been driven through the tissue, the ends of the legs areengaged with an anvil of the type typically having a pair of arcuateanvil pockets. This engagement causes the ends of the legs to be bent orrecurved back towards the tissue to secure the tissue sections togetherand/or to secure the auxiliary material to the tissue. These bent orrecurved portions of the staple legs are the tissue clenching portionsof the legs.

When attempting to secure relatively thick sections of tissue togetheror auxiliary material to a relatively thick tissue section, the sizingof the conventional staple is critical to ensure sufficient leg lengthsto traverse the tissue. Insufficient leg lengths will result inincomplete stapling of the tissue.

Further, when attempting to secure relatively thin sections of tissuetogether, or auxiliary material to the relatively thin tissue section,the sizing of the conventional staple is selected to ensure that thereis not an excess of leg length. Excess leg length may result in theclenching portions of the legs projecting substantially away from thetissue as well as causing the ends of the leg to recurve back into andpenetrate the tissue.

Therefore, it is desirable to provide a staple having a leg lengthsufficient for various tissue thicknesses expected to be encountered. Itis further desirable to provide a box shaped staple capable of beingformed such that the clenching portions of the legs lie parallel to andflush against the tissue to be secured. It is still further desirable toprovide a box staple assembly incorporating a staple plate to increasethe bearing area of the staple against the tissue and shield the tissuefrom the ends of the staple legs.

SUMMARY

There is disclosed a box staple including a backspan and a first legextending from the backspan. The first leg is divided into a firsttraversing leg portion and a first linear clenching leg portion by afirst bend. A second leg also extends from the backspan and is dividedinto a second traversing leg portion and a second linear clenching legportion by a second bend. At least one of the first and second linearclenching leg portions is oriented parallel to the backspan. In oneembodiment, both the first and second linear clenching leg portions areoriented parallel to the backspan.

At least one of the first and second traversing leg portions is orientedperpendicular to the backspan. In a specific embodiment, both the firstand second traversing leg portions are oriented perpendicular to thebackspan.

In one embodiment, a combined length of the first and second clenchingleg portions is less than an overall length of the backspan. In analternative embodiment, the combined length of the first and secondclenching leg portions is equal to an overall length of the backspan. Ina specific embodiment, the combined length of the first and secondclenching leg portions is greater than an overall length of thebackspan.

There is also disclosed a box staple assembly for use in tissue whichgenerally includes a backspan and first and second legs extending fromthe backspan. The first leg is divided into a first traversing legportion and a first linear clenching leg portion by a first bend. Thesecond leg is also divided into a second traversing leg portion and asecond linear clenching leg portion by a second bend. A staple plate ispositioned on the first and second legs between the backspan and thefirst and second linear clenching leg portions. At least one of thefirst and second linear clenching leg portions is oriented parallel tothe staple plate.

The staple plate has first and second holes to receive the first andsecond traversing leg portions respectively. An overall length of thestaple plate is greater than an overall length of the backspan and thedistance between the first and second holes is substantially equal tothe overall length of the backspan.

There is also disclosed a method of forming a box staple through tissueincluding the step of providing a box staple of having a backspan, afirst leg extending from the backspan and including a first bend zonelocated between the backspan and a first end of the first leg, and asecond the leg extending from the backspan and including a second bendzone located between the backspan and a second end of the second leg.The first and second ends of the first and second legs are driventhrough a tissue section. The first leg is impacted in the first bendzone with a first angled portion of a first anvil to form a first bendwithin the first bend zone and dividing in the first bend zone into afirst traversing leg portion and a first linear clenching leg portion.

The method further includes the step of impacting the first linearclenching leg portion with a first finishing surface of the first anvilto orient the first linear clenching leg portion parallel to thebackspan.

The method further includes the step of impacting the second leg in thesecond bend zone with a second angled portion of a second anvil to forma second bend within the second bend zone and dividing the second bendzone into a second traversing leg portion and a second linear clenchingleg portion.

The second linear clenching leg portion is impacted with a secondfinishing surface of the second anvil to orient the second linearclenching leg portion parallel to the backspan.

In one embodiment of the disclosed method, the first and second ends aredriven through tissue such that the backspan engages an upper surface ofthe tissue.

In a further embodiment of the disclosed method, a staple plate ispositioned over the first and second legs and engages an underside ofthe tissue prior to the step of impacting the first leg in the firstbend zone.

In a particular embodiment, the first linear clenching leg portion isoriented parallel to the staple plate.

DESCRIPTION OF THE DRAWINGS

Embodiments of the presently disclosed box staple and box stapleassembly are disclosed herein with reference to the drawings, wherein:

FIG. 1 is a side view, partially shown in section, of one embodiment ofa disclosed box staple formed through a pair of tissue sections;

FIG. 2 is an end view taken along line 2-2 of FIG. 1;

FIG. 3 is a top view taken along line 3-3 of FIG. 1;

FIG. 4 is a bottom view taken along line 4-4 of FIG. 1;

FIG. 5 is a side view, partially shown in section, of the box staple ofFIG. 1, inserted through the pair of relatively thick tissue sections,immediately prior to formation;

FIG. 6 is a side view similar to FIG. 5 during formation of the boxstaple through the pair of relatively thick tissue sections;

FIG. 7 is a side view similar to FIG. 6 after formation of the boxstaple through the pair of relatively thick tissue sections;

FIG. 8 is perspective view of the fully formed box staple;

FIG. 9 is a side view, partially shown in section, of the box stapleformed through a pair of relatively thin tissue sections;

FIG. 10 is a top view taken along line 10-10 of FIG. 9;

FIG. 11 is an end view taken along line 11-11 of FIG. 9;

FIG. 12 is a bottom view taken along line 12-12 of FIG. 9;

FIG. 13 is a side view, partially shown in section, of the box stapleimmediately prior to formation through the pair of relatively thintissue sections;

FIG. 14 is a side view similar to FIG. 13 during formation of the boxstaple through the pair of relatively thin tissue sections;

FIG. 15 is similar to FIG. 14 after formation of the box staple throughthe pair of relatively thin tissue sections;

FIG. 16 is a perspective view of a box staple assembly including a boxstaple and a staple plate;

FIG. 17 is a side view, partially shown in section, of the box stapleassembly formed through a pair of relatively thick tissue sections;

FIG. 18 is an end view taken along line 18-18 of FIG. 17;

FIG. 19 is a top view taken along line 19-19 of FIG. 17;

FIG. 20 is a bottom view taken along line 20-20 of FIG. 17;

FIG. 21 is a side view, partially shown in section, of the box stapleassembly immediately prior to formation through the pair of relativelythick tissue sections;

FIG. 22 is a side view, similar to FIG. 21, during formation of the boxstaple assembly through the pair of relatively thick tissue sections;

FIG. 23 is a side view, similar to FIG. 22, after formation of the boxstaple assembly through the pair of relatively thick tissue sections;

FIG. 24 is side view, partially shown in section, of the box stapleassembly formed through a pair of relatively thin tissue sections;

FIG. 25 is a top view taken along line 25-25 of FIG. 24;

FIG. 26 is a bottom view taken along line 26-26 of FIG. 24;

FIG. 27 is an end view taken along line 27-27 of FIG. 24;

FIG. 28 is a side view, partially shown in section, of an alternateembodiment of a staple assembly including a staple and an arcuate stapleplate formed through a pair of relatively thick tissue sections; and

FIG. 29 is a side view, partially shown in section, of the stapleassembly of FIG. 28 formed through a pair of relatively thin tissuesections.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the presently disclosed box staple and box stapleassembly will now be described in detail with reference to the drawingswherein like numerals designate identical or corresponding elements ineach of the several views. As is common in the art, the term ‘proximal”refers to that part or component closer to the user or operator, i.e.surgeon or physician, while the term “distal” refers to that part orcomponent further away from the user.

Referring to FIG. 1-4, and initially to FIG. 1, there is disclosed anembodiment of a universal or box staple 10 for use in various thicknessof tissues. Box staple 10 has the further advantage of providing uniformpressure against the underside of the tissues stapled as described inmore detail hereinbelow. Box staple 10 generally includes a backspan 12and first and second legs 14 and 16, respectively, extending distallyfrom backspan 12. Specifically, a proximal end 18 of first leg 14extends distally from a first end 20 of backspan 12 and a proximal end22 of second leg 16 extends distally from a second end 24 of backspan12. First leg 14 terminates in a tissue penetrating distal tip 26 andsecond leg 16 terminates in a tissue penetrating distal tip 28.

Box staple 10 is formed from a length of material having a generallyrectangular cross-section. Box staple 10 can be formed from any numberof biocompatible materials such as, for example, stainless steel,titanium, various malleable plastic materials, various bio-absorbablematerials etc. When formed from metallic materials such as stainlesssteel or titanium, box staple 10 can be formed by drawing and cutting alength of metallic wire, stamping box staple 10 from a sheet of metallicmaterial, etc. Likewise, when box staple 10 is formed from a plastic orbio-absorbable material, box staple 10 can be formed by injectionmolding, carving box staple 10 from a block of plastic material, etc.

As noted above, box staple 10 is designed for use in tissues of variousthicknesses, such as, for example, relatively thick tissues A and B. Inorder to accommodate the various thickness tissues without excessive orinsufficient compression of tissues A and B, first leg 14 has a firstbend zone 30 which extends substantially between proximal end 18 andtissue penetrating distal tip 26 of first leg 14. Depending upon thethickness of the tissues encountered, first leg 14 can be bent at anylocation within bend zone 30 to accommodate those tissues. This isfacilitated by the use of a pair of driven anvils as described in moredetail herein below. Second leg 16 also includes a second bend zone 32which extends substantially between proximal end 22 and tissuepenetrating distal tip 28 of second leg 16.

When box staple 10 is fully formed through relatively thick tissues Aand B, backspan 12 provides uniform compression on an upper surface C ofrelatively thick tissue section A (FIGS. 1 and 3). First leg 14 isformed with a first bend 34 in first transition zone 30 such that firstleg 14 is divided into a first, substantially linear traversing legportion 36 extending through relatively thick tissues A and B (FIG. 1)and a first substantially linear clenching leg portion 38 lying flushwith an underside D of relatively thick tissue section B (FIGS. 1 and4). It should be noted that, first bend 34 formed between firsttraversing leg portion 36 and first clenching leg portion 38 is asubstantially sharp or abrupt 90° bend in contrast to the relativelygradually curving bends typically associated with prior art staples.Likewise, second leg 16 is formed with a second bend 40 in second bendzone 32 which divides second leg 16 into a second substantially lineartraversing leg portion 42 extending through relatively thick tissuesections A and B (FIGS. 1 and 2) and a second substantially linearclenching leg portion 44 lying flush with underside D of relativelythick tissue section B. (FIGS. 1 and 4). Second bend 40 also forms arelatively sharp or abrupt 90° transition between second traversing legportion 42 and second clenching like portion 44. By maintaining firstand second clenching leg portions 38 and 44 in a relatively linear orstraight configuration against underside D of relatively thick tissuesection B, first clenching leg portion 38 and second clenching legportion 44 maintain a uniform compression against underside D withoutthe associated pinching or tip penetration of underside D as is commonwith the use of conventional staples whose leg distal ends are typicallyformed into a recurved shape penetrating back into the tissue.

As best shown in FIG. 1, when box staple 10 is formed through ofrelatively thick tissue sections A and B, the length L1 of backspan 12is greater than or equal to the combined lengths L2 and L3 of first andsecond linear clenching leg portions 38 and 44, respectively.

Referring now to FIGS. 5-7, and initially with respect to FIG. 5, theuse and formation of box staple 10 with relatively thick tissue sectionsA and B will now be described. Initially, the dimensions of box staple10 are chosen such that legs 14 and 16 have overall lengths L4 and L5which are substantially greater than the anticipated combine thicknessesof any tissues to be encountered. Furthermore, each of the overalllengths L4 and L5 of first and second legs 14 and 16, respectively, isgreater than half the overall length L1 of backspan 12. This ensuressufficient leg length to traverse and secure both relatively thick andthin tissue sections. Box staple 10 is initially driven throughrelatively thick tissue sections A and B by engaging backspan 12 with astaple driver (not shown) thereby driving first and second tissuepenetrating distal tips 26 and 28, respectively, through tissue sectionsA and B.

Referring to FIG. 6, thereafter, a pair of anvils, such as, for example,first and second driven anvils 50 and 52, are driven laterally againstfirst and second staple legs 14 and 16 to form box staple 10 throughrelatively thick tissue sections A and B. First and second driven anvils50 and 52 generally include respective first and second angled surfaces54 and 56 and respective first and second finishing surfaces 58 and 60.First and second angled surfaces 54 and 56 are provided to initiallyimpact or impinge against first and second legs 14 and 16 within therespective first and second bend zones 30 and 32 to initially createfirst and second bends 34 and 40. This divides first bend zone 30 offirst leg 14 into first traversing leg portion 36 and first linearclenching leg portion 38. Similarly, this divides second bend zone 32into second traversing leg portion 42 and second linear clenching legportion 44.

Referring to FIG. 7, as first and second anvils 50 and 52 are driven tothe final position, first and second linear clenching leg portions 38and 44 engaged by relatively linear finishing surfaces 58 and 60 ofdriven anvils 50 and 52, respectively such that first and second linearclenching leg portions 38 and 44 are brought flush into engagement withunderside D of relatively thick tissue section B. As noted here inabove, when box staple 10 is used in relatively thin tissue sections,the combined lengths L2 and L3 of first and second clenching legportions 38 and 44, respectively, are substantially less than or equalto the overall length L1 of backspan 12.

Referring now to FIGS. 8-12, and initially with regard to FIG. 8, boxstaple 10 is illustrated in the configuration it assumes when usedthrough a pair of relatively thin tissue sections. Specifically, whenbox staple 10 is formed through relatively thin tissue sections, each ofthe lengths L2 and L3 of respective first and second linear clenchingleg portions 38 and 44 are greater than the overall length L1 ofbackspan 12.

As shown in FIG. 9, first and second traversing leg portions 36 and 42pass through thin tissue sections E and F. First and second the linearclenching leg portions 38 and 44 lie parallel to tissue section F. Asbest shown in FIG. 10, backspan 12 engages an upper surface G of tissuesection E while first and second linear clenching leg portions 38 and 44engaged an underside surface H of tissue G.

As best shown in FIGS. 8, 11 and 12, the excess lengths of first andsecond clenching leg portions 38 and 44 are accommodated by allowingthem to lie in parallel relation to each other against underside F oftissue H. Thus, box staple 10 functions as a universal staple suitablefor use with both thick and thin tissue sections without risk ofpenetrating the tissue sections with first and second tissue penetratingdistal tips 26 and 28 of respective first and second legs 14 and 16.

Referring now to FIGS. 13-15, in order to form box staple 10 throughpair of relatively thin tissue sections E and F, box staple 10 isinitially driven through tissue sections E and F. Thereafter, drivenanvils 50 and 52 impact staple legs 14 and 16 to initially begin to bendstaple legs 14 and 16. As shown in FIG. 14, angled faces 54 and 56 ofdriven staples 50 and 52 initially form bends 34 and 40 to createrespective first and second traversing leg portions 36 and 42 and firstand second linear clenching leg portions 38 and 44. Thereafter, withreference to FIG. 15, finishing surfaces 58 and 60 of driven anvils 50and 52 engage first and second linear clenching leg portions 38 and 44to form first and second linear clenching leg portions 38 and 44 againstunderside H of tissue F and, more importantly, parallel to backspan 12.Thus, box staple 10 is particularly suited to use with relatively thintissue sections such that first and second linear clenching leg portions38 and 44 a lie flush against the tissue to be stapled.

Referring now to FIGS. 16-20, and initially with regard to FIG. 16 thereis disclosed a box staple assembly 70 including box staple 10 and apledget or staple plate 72. Staple plate 72 increases the surface areaengaging a tissue being stapled as well as protecting the tissue fromengagement with staple legs 14 and 16 upon crimping of box staple 10about tissue. Box staple 10 is as described herein above includingbackspan 12 and legs 14 and 16 extending from backspan 12.

Staple plate 72 is substantially rectangular having first and secondholes 74 and 76 adjacent first and second ends 78 and 80, respectively,of staple plate 72. First and second holes 74 and 76 are configured toreceive first and second legs 14 and 16, of box staple 10, therethrough.Staple plate 72 has an overall length L4 which is greater than thelength L1 of backspan 12 (FIG. 1). Additionally, the spacing or lengthL5 between holes 74 and 76 is substantially identical to the length L1of backspan 12.

As best shown in FIGS. 17 and 18, box staple assembly 70 is provided tosecure a pair of tissue sections, such as, for example, tissue sectionsI and J. Backspan 12 engages an upper surface K of tissue section I(FIG. 19) while an upper surface 82 of staple plate 72 engages a lowersurface L of tissue section J (FIG. 20).

Referring to FIG. 20, as noted herein above, staple plate 72 protectstissue section J from engagement with first and second clenching legportions 38 and 44 of first and second legs 14 and 16, respectively.Specifically, upon formation of staple 10 through tissue sections I andJ, staple plate 72 is interposed between tissue section J and first andsecond clenching leg portions 38 and 44.

Referring to FIGS. 21-23, the use of box staple assembly 70 to secure apair of relatively thick tissue sections I and J together will now bedescribed. With reference to FIG. 21, initially, box staple 10 is drivenby a staple driver (not shown) toward tissue sections I and J such thatfirst and second legs 14 and 16 penetrate tissue sections I and J untilbackspan 12 engages upper surface K of tissue section I. Staple plate 72is positioned against undersurface K of tissue section J and legs 14 and16 are extended through holes 74 and 76 a staple plate 72. This bringsupper surface 82 of staple plate 72 into engagement with undersurface Kof tissue section J.

With reference to FIGS. 21 and 22, thereafter, first and second drivenanvils 50 and 52 are moved inwardly toward first and second legs 14 and16. Upon engagement of first and second angled surfaces 54 and 56 withfirst and second legs 14 and 16, first and second legs 14 and 16 areinitially bent within respective bend zones 30 and 32 to form first andsecond bends 34 and 40 within first and second legs 14 and 16. As notedhere in above, first bend 34 divides first leg 14 into first traversingleg portion 36 and first linear clenching leg portion 36 while secondbend 40 divides second legs 16 into second traversing leg portion 42 andsecond linear clenching leg portion 44. Notably, the extension of firstand second legs 14 and 16 through first and second holes 74 and 76 instaple plate 72 facilitate forming bends 74 and 76 at substantiallyright angles relative to first and second traversing leg portions 36 and38 of first and second legs 14 and 16, respectively.

Finally, with reference to FIG. 23, engagement of first and secondfinishing surfaces 58 and 60 of the first and second driven anvils 50and 52 with first and second linear clenching leg portions 38 and 44serve to secure first and second linear clenching leg portions 38 and 44against underside 84 of staple plate 72 thereby securing staple plate 84against underside L of tissue section J.

Referring now to FIGS. 24-27, the use of box staple assembly 70 tosecure a pair of relatively thin tissue sections, such as, for example,tissue sections M and N will now be described. The method disclosedherein with respect to relatively thin tissue sections M and N issubstantially identical to the method disclosed herein above withrespect to relatively thick tissue sections I and J. Initially, withreference to FIG. 24, staple 10 is driven by a staple driver (not shown)such that first and second legs 14 and 16 are driven through tissuesections M and N until backspan 12 engages an upper surface O of tissuesection M (FIG. 25). First and second legs 14 and 16 are then insertedthrough holes 74 and 76 of staple plate 72. Thereafter, first and seconddriven anvils 50 and 52 (FIGS. 21-23) are moved to form first and secondlinear clenching leg portions 38 and 44 against underside 84 of stapleplate 72 (FIG. 26).

As best shown in FIGS. 26 and 27, similar to that disclosed herein abovewith respect to box staple 10 in FIGS. 11 and 12, first and secondlinear clenching leg portions 38 and 44 are in a side-by-side andoverlapping relation with respect to each other due to the excesslengths of legs 14 and 16 wine used through relatively thin tissuesections M and N. In this manner, the provision of box staple 10 havingfirst and second legs 14 and 16 with overall lengths greater then atleast the overall length of backspan 12 allows box staple 10 to functionas a universal staple suitable for use with various thicknesses oftissue. As noted herein above, the provision of staple plate 72 providesadditional surface bearing area against the tissue section whilefacilitating forming an abrupt 90° bend within first and second legs 14and 16.

Referring now to FIGS. 28 and 29, while staple plate 72 has beendisclosed for use with box staple 10, staple plate 72 may be formed of amaterial which allows staple plate 72 to be used with a staple and 90similar to box staple 10 in situations wherein staple 90 is formed withconventional anvils. As used herein, the term “conventional anvils”refers to those anvils having arcuate anvil pockets resulting in arcuaterather than linear clenching leg portions in the formed staple.

For example, with reference to FIG. 28, staple 90 includes a backspan 92having first and second legs 94 and 96 extending from backspan 92. Inuse, staple 90 is driven through relatively thick tissue sections Q andR resulting in first and second traversing leg portions 98 and 100extending through tissue sections Q and R while backspan 92 engages anupper surface S of tissue section Q. First and second legs 94 and 96 areextended through holes 74 and 76 in staple plate 72 and are clenchedagainst staple plate 72 by arcuate anvil pockets formed in an anvilassociated with a conventional stapler (not shown).

Similarly, with reference to FIG. 29, when used in conjunction withrelatively thin tissue sections U and V, backspan 92 engages an uppersurface W of tissue section U while traversing leg portions 98 and 100extending through tissue sections U and V. Staple plate 72 bears againstan undersurface X of tissue section V. First and second linear clenchingleg portions 102 and 104 of first and second legs 94 and 96 are formedinto a roughly arcuate overlapping relation due to the excess length oflegs 94 and 96.

It will be understood that various modifications may be made to theembodiments disclosed herein. For example, the legs of the disclosed boxstaple maybe heat treated at specific points to facilitate the formationof the abrupt 90° bend between the traversing portion of the leg and thelinear clenching portion of the leg. Further, alternative embodiments ofanvils may be provided to form the substantially right angle withintheir respective legs. Additionally, the disclosed box staple may beformed from any shape memory alloy such that the right angle between thetraversing leg portion and the linear clenching leg portion is formed ata predetermined location along the length of the leg. Therefore, theabove description should not be construed as limiting, but merely asexemplifications of particular embodiments. Those skilled in the artwill envision other modifications within the scope and spirit of theclaims appended hereto.

What is claimed is:
 1. A method of forming a substantially box-shapedstaple through tissue comprising: providing a substantially box-shapedstaple having a backspan, a first leg extending from the backspan andincluding a first bend zone located between the backspan and a first endof the first leg, and a second leg extending from the backspan andincluding a second bend zone located between the backspan and a secondend of the second leg; driving the first and second ends of the firstand second legs through a tissue section; and driving a first angledportion of a first anvil laterally in a direction parallel to thebackspan into the first bend zone of the first leg to bend and dividethe first leg into a first traversing leg portion and a firstsubstantially linear clenching leg portion.
 2. The method as recited inclaim 1, further comprising impacting the first substantially linearclenching leg portion with a first finishing surface of the first anvilto orient the first substantially linear clenching leg portionsubstantially parallel to the backspan.
 3. The method as recited inclaim 2, wherein the first finishing surface of the first anvil islinear.
 4. The method as recited in claim 2, further comprising drivinga second angled portion of a second anvil laterally in a directionparallel to the backspan into the second bend zone of the second leg tobend and divide the second leg into a second traversing leg portion anda second substantially linear clenching leg portion.
 5. The method asrecited in claim 4, wherein steps of driving the first and second anvilslaterally includes forming a first bend having a 90° transition betweenthe first traversing leg portion and the first substantially linearclenching leg portion of the first leg and forming a second bend havinga 90° transition between the second traversing leg portion and thesecond substantially linear clenching leg portion of the second leg. 6.The method as recited in claim 4, further comprising impacting thesecond substantially linear clenching leg portion with a secondfinishing surface of the second anvil to orient the second substantiallylinear clenching leg portion substantially parallel to the backspan. 7.The method according to claim 6, wherein the first finishing surface ofthe first anvil and the second finishing surface of the second anvil arelinear.
 8. The method as recited in claim 1, wherein the first andsecond ends of the first and second legs are driven through tissue suchthat the backspan engages an upper surface of the tissue section.
 9. Themethod as recited in claim 1, further comprising positioning a stapleplate over the first and second legs and into engagement with anunderside of the tissue section prior to the step of driving the firstanvil laterally.
 10. The method as recited in claim 9, wherein the firstsubstantially linear clenching leg portion is oriented substantiallyparallel to the staple plate.
 11. The method as recited in claim 9,wherein the staple plate has an arcuate surface.
 12. The method asrecited in claim 1, wherein the step of driving the first anvillaterally includes forming a first bend having a 90° transition betweenthe first traversing leg portion and the first substantially linearclenching leg portion of the first leg.